1. Field of the Invention
The present invention relates generally to marine streamers, and in particular, to a multiple wire sealing mechanism used in marine streamer assemblies.
2. Description of Related Art
In marine seismic surveying, seismic signals are detected by hydrophones mounted in a cable commonly referred to as a marine streamer. The streamer is coupled to a cable tied to a towing ship which, in operation, tows the streamer along a prescribed line of survey. In general, the marine streamer, which may be 2,000 feet or more in length, consists of a central stress member surrounded by a plurality of electrical or optical conductors. The conductors are connected to a corresponding plurality of hydrophone groups, and transmit the hydrophone signals to a recording device on the towing ship. For protection from abrasion and salt water corrosion, the stress member and the conductors are enclosed in a plastic sheath.
Generally speaking, it is preferable to tow the marine streamer at a controlled depth of around 35-40 feet. Typically, a protective clear plastic flexible tube of about 3 inches in diameter surrounds the marine streamer. However, before a seismic shooting project starts, the cable must be balanced so that it can be pulled at a controlled depth. Balancing of the streamer is accomplished by filling the plastic tube with a kerosene-like liquid which is lighter than water (and commonly referred to as "noroma"), and/or by adding lead tape to the exterior of the plastic tube.
A typical marine streamer is comprised of many individual sections which may be up to 300 feet in length. Each section has male and female couplers disposed on each end of the section so that sections may be connected to each other so as to make up the overall marine streamer. The multiple conductors, which may number as many as 40 or more, terminate in a connector insert disposed in the respective male and female couplers, so that the seismic information received from the hydrophone may be transmitted to the towing ship.
One major problem encountered with conventional marine streamer connectors is that the conductors, such as wires and terminating pins disposed in the connector insert, are exposed to the noroma in the given section of marine cable. Additionally, if the external skin of the section is punctured or otherwise damaged, the conductor wires and pins are exposed to salt water. Presently, practitioners of the art attempt to remedy this problem by application of a suitable potting compound to the backside of the connector. Typically, however, this technique has proven ineffective because the potting compound has proven ineffective in preventing the ingress of salt water; and secondly, the presence of a viscous potting compound frustrates the repair and/or replacement of electrical and fiber optic contacts in the coupler.
Similar problems have been encountered with program modules which are typically positioned in conventional marine streamer assemblies. Typical program modules contain mating printed circuit boards to which are attached the conductor wires running through the marine streamer. The program module allows the seismic crew to change the configuration of the hydrophone arrays in a given section that will conduct the seismic sampling.